<!DOCTYPE html>
<html lang="cn">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style type="text/css"></style>
   
</head>
<body>
  <script>
        var num = 556;
        var num = 12e-3;
        var num = 12e3;
        var num = 12e+3;

        var num = 12e-3-3;
        var num = 12e3*3;

        //var num = 0b110; //2进制
        //var num = 010; //8进制
        //var num = 0xff; //16进制

        console.log(num);
        console.log(typeof num);

        //Not a Number
        var num = NaN;
        console.log(num);

        console.log(NaN+100);


        console.log("===========================");
        console.log(NaN*0);
        console.log("aaa"*0);
        console.log("123"*0);
        console.log("123aaa"*0);
        console.log(NaN/0);



        if(NaN)
        {
            console.log(true);
        }else
        {
            console.log(false);
        }
        if(NaN==NaN)
        {
            console.log(true);
        }
        else
        {
            console.log(false);
        }
        //把其他值转换成数值是,转成功成为数值,转不成就成NaN
        //Number()  parseInt()  parseFloat()
        //
        var a = 'hhhhh';
        var a ='';
        var a ='555aaa';
        var a ='555.99aaa';
        var a = true;
        var a = false;
        var a = null;
        var a = undefined;

        // var n = Number(a);
        var n = parseInt(a);
        // var n = parseFloat(a);
        
        console.log(n);
        console.log(typeof n);

        console.log(isNaN(99));
        console.log(isNaN('asdada'));
        console.log(isNaN("55aaa"));
        
   </script>
</body>
</html>


